A known vehicle door opening and closing device is disclosed in U.S. Pat. No. 5,806,246A. The vehicle door opening and closing device disclosed is a cable-driven type in which a cable is used for a power transmission related to an opening and closing driving of a sliding door. The device disclosed includes a take-up pulley on a lower side of a step panel so as to be rotatably driven by an electric motor, and driven pulleys on front and rear end portions of the lower face of the step panel. Then, two cables whose respective one ends are connected to a portion of a sliding door are in contact with the take-up pulleys.
In the aforementioned structure, when one cable is drawn out while the other cable is taken up, for example, by rotatably driving the cable take-up pulley by means of the electric motor, the sliding door is opened. Meanwhile, when one cable is taken up while the other cable is drawn out, the sliding door is closed.
The aforementioned sliding door is opened or closed since a roller provided on the door is guided onto a guide rail of a guide portion. A front end of the guide rail is bent towards an inner side in the vehicle width direction while a rear end extends in the rearward direction of the vehicle. This is for pushing the sliding door in the vehicle exterior direction immediately after the sliding door is opened from a fully closed state, or pulling the sliding door in the vehicle interior direction immediately before the sliding door is brought in a fully closed state.
According to the sliding door disclosed, when the roller provided on the sliding door passes through the bent portion of the guide rail, an effective length of a path of the cable is significantly changed. Therefore, in order to absorb looseness of the cable in association with change of the effective length, a pulley is provided for tension control in a middle of the path of the cable, thereby requiring a comprehensive structure, increase of the number of parts, and the like.
Thus, a need exists for a vehicle door opening and closing device that can absorb looseness of a cable by a simple structure, and improve reliability of an opening and closing driving of the vehicle door.